





from math import factorial

def     a_       (					lowerCAmelCase_ :     int = 20      ):
   __lowerCAmelCase				      =      2 * n  # middle entry of odd rows starting at row 3 is the solution for n = 1,
   # 2, 3,...
   __lowerCAmelCase				      =      n // 2

   return int(factorial(lowerCAmelCase_      ) / (factorial(lowerCAmelCase_      ) * factorial(n - k      ))      )


if __name__ == "__main__":
     import sys

     if len(sys.argv) == 1:
          print(solution(20))
     else:
          try:
               _snake_case    :       Union[str, Any]		       =    int(sys.argv[1])
               print(solution(n))
          except ValueError:
               print('Invalid entry - please enter a number.')






'''simple docstring'''

from typing import TYPE_CHECKING

from ...utils import _LazyModule


SCREAMING_SNAKE_CASE__     :						Dict	=  {'''tokenization_wav2vec2_phoneme''': ['''Wav2Vec2PhonemeCTCTokenizer''']}


if TYPE_CHECKING:
			from .tokenization_wavaveca_phoneme import WavaVecaPhonemeCTCTokenizer
else:
			import sys

			SCREAMING_SNAKE_CASE__     :						Dict	=  _LazyModule(__name__, globals()['''__file__'''], _import_structure, module_spec=__spec__)




